Grill the peaches and jalapeno on a grill at medium high heat. Rotate the jalapeno to insure it is grilled evenly on all sides. Once the peaches are sizzling and the jalapeno is nice browned; remove from heat to cool.

Remove the blistered skin from the jalapeno and peel the skin from the peaches (should pull off easily after being grilled).

Combine the peaches, jalapeno, brown sugar simple syrup, lime juice and tequila together in a blend and blend until smooth. Put the mixture into the fridge to chill for at least an hour.

Rub the rims of glasses with a cut lime quarter and dip in mixture of brown sugar and margarita salt (or kosher salt). Fill the glasses with ice.

Pour mixture into glasses and garnish with a lime wedge and peach slice.